On Tue, June 24 at 8:03 AM EDT
David selby <[EMAIL PROTECTED]> wrote:
> Colin Watson wrote:
>
> >On Mon, Jun 23, 2003 at 07:57:07PM +0100, David selby wrote:
> >
> >
> >>My bash masterpeice is almost complete ... I have one last problem
> >that >no matter how many "" or '' I use I cannot get around.
> >>
> >>I need to use an if...then construct to check that my 4 digit date
> >field >is 4 numerical digits.This is for error checking. I thought
> >[sets] was >the way to go ....
> >>
> >>if [ $fourdig = [0-9][0-9][0-9][0-9] ]; then ......
> >>
> >>
> >
> >Nope - read the expr(1) manual page to find out how to do pattern
> >matching. And yes, you do need quotes (single quotes, unless you know
> >you need to interpolate something within double quotes) around that
> >to stop the shell accidentally expanding it to any files with
> >four-digit filenames in the current directory.
> >
> >
> >
> >>It has occured to me that perhaps [sets] are not allowed as a
> >>conditional test.
> >>
> >>
> >
> >They aren't. [ ... = ... ] tests *equality*, not pattern matching.
> >
> >Cheers,
> >
> >
> >
> Yes, fundermental misunderstanding on my part, this grep ^[0-9]*$ is
> an ingenious solution, Im still trying to get my head around .....
Will that test for 4 digits or a string of digits? What about this
little change:if echo $fourdig | grep '^[0-9]\{4\}$' > /dev/null 2>&1;
?
Shawn Lamson
[EMAIL PROTECTED]
Debian GNU/Linux 3.0
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